The present invention relates to warning lights used on motor vehicles. More particularly the present invention relates to side warning lights used on elongated motor vehicles such as truck trailer combinations, truck tanker combinations or buses, for example.
There has been a growing tendency to recognize the importance of having lights illuminated on automobiles and trucks even during the daylight hours. In various jurisdictions such as Sweden and Canada, for example, motor vehicles are required to be wired so that the lights are energized as soon as the ignition is turned on. It is not possible to start the engine of the motor vehicle without the lights being energized.
In automobiles, this generally applies to the headlights and sometimes to the brake lights as well. It has been recognized that when vehicles are approaching with the headlights on, the driver of an oncoming vehicle will more readily focus on the moving vehicle coming towards the driver. This is particularly important on long trips when the drivers may be fatigued. Also during twilight hours, many drivers do not realize that their vehicles are not easily visible to oncoming traffic without their headlights being turned on.
It has been recognized for many years that using reflective lights on the rear of motor vehicles at least permits a trailing vehicle to illuminate the reflectors of a vehicle in front even if the lights are not turned on. It has become increasingly important that vehicle lights be automatically energized even without the driver's action. It is very common to have sensors in motor vehicles which automatically turn on the headlights when the ambient light becomes lower than an acceptable minimum.
In recognizing these problems, U.S. Pat. No. 4,952,909 has been issued to the same inventors as the present application. This patent describes an early warning system which can anticipate the braking of a vehicle in front of another vehicle. The illustrated embodiment of the invention described in that patent provides a yellow/amber warning light closely adjacent to the high mounted center brake light now required on all vehicles manufactured to United States standards. It has been found that with such yellow/amber warning light the driver or drivers in the vehicles behind such motor vehicle will focus on the yellow/amber light that is on continuously. When the brake light is applied, the trailing drivers will readily notice the illumination of the braking light because, as described in that patent, the yellow/amber light will be deenergized and the red brake light will be energized. This change in light pattern is readily noticeable by drivers of trailing vehicles.
It is well known that saving even a fraction of a second in reaction time by early recognition of the braking of a vehicle in front of a trailing vehicle will prevent many rear end collisions.
The problems of course are magnified when elongated vehicles, such as buses, truck and trailers, truck and tankers, etc. are moving along the same highways with automobiles and other motor vehicles. This has already been recognized by the United States Department of Transportation by requiring running lights to be illuminated or energized at all times on such long trailers, by having yellow colored front running lights and red colored rear running lights.
In fact, vehicles over a prescribed length also require that an additional light be mounted on the side generally at the mid point between the front and rear running lights. The reason for this is that a large majority of accidents involving truck trailer and truck tanker combinations are collisions from the side. As an elongated vehicle proceeds through an intersection, the headlights of the truck, for example and even the front running lights, may be past the end of the intersection while the elongated body of the trailer or bus will still be in the intersection. A driver approaching at right angles to the path of the elongated vehicle will not always recognize that such vehicle is still in the intersection. This often can result in the approaching vehicle running into the side of the trailer of the truck trailer combination.